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PCU training 2
pulmonary and neuro
Question | Answer |
---|---|
Why does the process of ventilation occur? | A gradient exists between the atmospheric pressure and intrapulmonary pressures. |
Chemoreceptors (central) | Found in the medulla. responds to the hydrogen ion concentration in the extracellular fluid (acidotic) that surrounds them. |
What is perfusion? | Alveolar vent. occurs at a rate of 4L/min & pulmonary capillary perfusion should be about 5L/min, with a relative matchup of ventilation and perfusion in a ratio of 4 to 5 or 0.8 (V/Q match) |
What are ventilation/perfusion mismatches? | *Intrapulmonary shunting: when some alveoli are not able to vent and there is no opportunity for gas exchange but blood is still perfusing the area.*High vent perfusionLow vent perfusion:when adequate blood flow surrounds underventilated alveoli |
Respiratory Gas exchange | *gas exchange occurring at the alveolarcapillary membrane(external respiration)& at the level of capillary and cell(internal respiration)*primarily accomplished by diffusion |
chemoreceptors (peripheral) | Found in the arch of the aorta and in the common carotid arteries.Increase ventilation in direct response to arterial oxygen concentration |
Mechanisms for regulating ventilation | coordination of 3 mechanisms:1)CNS(the controller)2)Thoracic musculature(the effectors)3)a variety of sensors,including central and peripheral chemoreceptors. |
Controller of Ventilation | CNS: 1) brainstem2) cerebral cortex3) neurons |
Effectors of Ventilation | *stimulated by the CNS*medulla sends impulse down cervical plexus to phrenic nerve, which then stimulates the diaphragm to contract.the connection of diaphragm to ribs causes lower ribcage to move outward as well.ribs expand and ribcage lifted. |
Lung Volumes | Tidal volumeInspiratory volume*Expiratory volume*Residual volume- have to have to keep lungs open. |
Gas transport | *getting O2 from lungs to cells in the bld*done by pumping action of hrt*bld carries O2 from lungs to tissues, then diffusion drives the O2 across the capillary wall into the tissue and cell |
Two ways O2 is carried in the blood | 1)Dissolved in Plasma2)attached to Hmg |
Hypoxemia | the decrease in measured O2 in the blood- either as PaO2 or saturation. can be measured directly by blood gas analysis*cause is a V/Q defect resulting in hypoventilation |
Hypoxia | a decrease in O2 availability at the tissue level. cannot be measured directly |
oxyhemoglobin dissociation curve (left of the curve) | decreased temperature,increased pH, and decreased 2,3 DPG |
Pulmonary Artery Hypertension (PAH) | *characterized by elevated Pulmonary artery pressure and pulmonary vascular resistance leading to right ventricular failure and death.*incurable |
Pulmonary Artery Hypertension causes | *Primary: familial or idiopathic (unknown)*Secondary: other diseases such as HIV infection, collagen vascular disorders, PE, portal HTN, congenital hrt disease, interstitial lung disease, COPD, and sleep apnea |
PAH definition | A mean pulmonary artery pressure >25 mmHG with normal pulmonary capillary wedge pressure.normally, the pulmonary vasculature is a low-pressure system. |
Diagnosing PAH | *right sided cardiac cath with vasoreactivity testing is the gold standard.*12-lead EKG, CXR shows enlarged hrt, prominent pulmonary arteries, and underlying lund disease.PFT'sABG's |
PAH conventional drug therapies | *diuretics:manage volume overload due to right ventricular failure.*supplemental O2:hypoxia is a potent vasoconstrictor,most patients are on supplemental O2 *Digoxin:inotropic agent for hrt fail*anticoagulants*Ca chnl block:decreases vasospasms |
Care for PAH | *increase CO,decrease pulmonary artery pressures. |
common symptoms in PAH | dyspnea, fatigue, presyncope or syncope, peripheral edema and ascites*worsening of symptoms signals progressions of disease and may need to increase meds |
Chronic Obstructive Pulmonary Disease (COPD) Hallmark signs | *chronic cough, expectoration,varying levels of dyspnea on exertion, and a decrease in expiratory airflow that does not respond to pharmacologic interventions*exhaustion*anxiety*Tachycardia*Vent dysrhythmias |
COPD interventions | Maintain oxygenation & ventilation. Manage CO2, sedation, hypoxic drive, and ventilation |
COPD clinical presentation | *will be most comfortable sitting upright and leaning forward with arms supported on the overbed table. *CXR= flattened diaphragm*Pt color will change from pink to dusky and diaphoretic as they deteriorate |
Chronic Bronchitis | *Pt has a chronic cough with sputum production for three months of the yr for two consecutive yrs. *Increased mucus gland size & bronchial wall thickness *presence of cor pulmonale with increased right sided hrt failure |
Pulmonary Embolism | *emboli lodges into one of the pulmonary vessels disrupting blood flow to an area of the lung.Deep veins of legs most common origin of blood clots |
PE three disposing factors (Virchow's Triad) | 1) Venous stasis2) altered coagulability of the blood3) damage to the vessel walls |
Acute PE clinical presentation | ABG results, Ventilation-perfusion lungs scan, spiral CT angiography, pulmonary angiogram*dyspnea, pleuritic chest pain, dry cough, & anxiety with a feeling of impeding doom. *tachypnea, rales, tachycardia, and fever |
PE medical interventions | *continuous heparin drip and warfarin may be started*require placement of venous filter in inferior vena cava below the arteries to prevent further migration of emboli*O2 and ventilation to attempt to reverse pulmonary htn. may include intubation |
Atelectasis | Groups of alveoli that have collapsed or unable to expand.*leads to alveolar hypoventilation and secondarily to vent-perf mismatch |
Significant findings in Atelectasis | *inspiratory crackles or popping noises.*changes in vital signs: slight temperature elevation and mildly increased hrt rate and respiratory rate |
Atelectasis medical interventions | *Low-flow O2*IS*Positive airway pressure: cpap, bipap, or peep |
Pneumonia | Inflammation of the lung caused by an infecting agent that usually leads to an area of consolidation within the parenchyma |
PNA symptoms | *Fever, chills, dyspnea, and cough(productive or nonproductive). Purulent sputum*Crackles at the end of inspiration that does not clear with cough*pain in the area of consolidation*limited chest expansion on affected side*CXR=pulmon infiltrate |
PNA interventions | *Identify organism thru bld and sputum and ABX therapy*Hydration with IVF and nutritional support*mech vent may be required if pt develops acute respiratory failure |
Asthma | *chronic disorder of airways that results in airflow obstruction,broncial hyper-responsiveness & an underlying inflammation*airflow obstruction*largely reversible*Status asthmaticus=SOB,cough,wheeze,chest tightness. airway narrows |
Immune response | *stimulated by exposure to irritant that sets up inflammation in airways.*contributes to bronchospasm, increased mucus production, and mucosal edema*vent-perf mismatch leads to hypoxemia and tissue hypoxia causing further vasoconstriction |
P/F ratio | Easily calculated: just divide the PaO2 value by the FiO2 (as decimal)*normal= 400-500 |
compensated ABG | Differs from a normal ABG in that PaCO2 and HCO3 will both be abnormal |
Normal values of P/F ratio | 400-500 |
Negative Inspiratory Force | *critical for maintaining a clear airway.*Good Predictorof patients ability to takea deep breath and cough.*-20cmH2O |
V/Q scans | *Done to evaluate for vent/perfusion mismatches, most commonly when a pulmonary embolus is suspected |
Preoperative considerations for Thoracic surgery | *lung function*cardiac function*tumor removal*pain management |
Clinical approach to thoracic surgery | *patient poisitioning and ventilation important. usually posteriolateral but depends on location of area*et tube with double lumen is common*Must evaluate for mediastinal shift. * |
mostly likely to occur during immediate postoperative period | hemorrhage |
Postoperative indicators of hemorrhage | *drainage volume exceeding >100ml per hour*sudden increase in drainage*fresh red blood |
mediastinal shift | accumulation of fluid or an increase in pressure on the surgical side*remove air or fluid on surgical side |
Cardiovascular complications | *occurs when large volume of the lung tissue and the pulmonary vascular bed is resectioned*use vasoactive meds to optimize cardiac function |
pain indicators for thoracic surgery | *tachypnea with or without hypoventilation*tachycardia*elevated BP*grimacing,splinting, and moaning*increased restlesness or an unwillingness to move |